The art describes systems for binding sheets using adhesives including pressure sensitive adhesive, which systems include cover structures and/or devices used in binding such sheets and produce various types of bound documents. Many such systems have included methods and devices adapted for binding sheets by disposing the sheets in a stack with narrow side surface portions of the sheets adjacent their spine edges exposed beyond the spine edges of overlying sheets, and applying a layer of adhesive over the spine edges and exposed narrow side surface portions to bind the stack. Such a system in which a layer of pressure sensitive adhesive already adhered to a flexible backing is adhered over the spine edges and exposed narrow side surface portions so that the flexible backing and layer of pressure sensitive adhesive bind the stack into a bound document is described in U.S. Pat. No. 3,188,144.
While such systems produce useful bound documents that can be formed by persons with no particular binding skill in offices or homes without the need for passing mechanical binding devices through openings in the sheets that can obstruct information on the sheets and restrict easy opening of the document, known documents of this type have a somewhat unconventional appearance and are somewhat limited in the number of sheets that can be conveniently bound due to the offset spine edges of the bound sheets.